Boxelder bugs, Boisea trivittata (Say), are a nuisance, especially during the cool autumn months when they cluster in large numbers on the sides of trees, houses and other structures. This pest enters buildings through cracks and openings and spends the winter hibernating behind exterior siding and in attics, soffits, wall voids, window/door casings and similar protected areas. Boxelder bugs may also take refuge in soil and leaf litter next to foundations. With the onset of warmer weather in late winter and spring, these bugs become active and emerge from their overwintering sites. As they attempt to escape to their natural habitat outdoors, some inadvertently disperse inward into living areas, emerging from beneath baseboards, behind windo...